Question

What is the difference between geometric isomers and optical isomers?

Answer 1

Before knowing about the geometrical isomers and optical isomers the basics is they both are stereoisomers. Stereoisomers are organic compounds containing the same molecular formula, but different spatial arrangement of the atoms. The sequence of chemical bonds is also the same for these isomers.

Complete answer:
Optical isomers – these are the isomers that have the same chemical formula and the same connectivity of atoms but a different spatial arrangement. These compounds appear as mirror images of each other. These mirror images are non-superimposable.
The optical isomers of the same compound have similar physical properties and differ only in the property of rotation of plane-polarized light and are known as enantiomers. Here, one isomer rotates the plane-polarized light into the right hand side known as dextro rotatory while its optical isomer rotates the same plane-polarized light to the left hand side known as laevo rotatory.
Geometrical isomers – these are stereoisomers that have the same substituents attached differently to a carbon-carbon double bond. This type of isomer occurs because the double bond between carbon atoms avoids the ability to rotate around the axis of the double bond and this in turn gives fixed positions to the isomer.
Geometrical isomers are also called cis-trans isomers because these isomers come in pairs, and can be named as cis-isomer and trans-isomer.
The key difference between optical and geometrical isomers is that optical isomers are pairs of compounds which appear as mirror images of each other whereas geometrical isomers are pairs of compounds containing the same substituents attached to a carbon-carbon double bond differently.

Note:
The main criteria for the organic compounds to exhibit.
Optical isomerism
-Planes of symmetry
-Non-superimposable mirror images
-Chirality
Geometrical isomerism
-It must contain a carbon-carbon double bond in the molecule
-Two unlike atoms or groups must be linked to each doubly bonded carbon atom.